Kmetiuk Louise Bach, Paula Warley Vieira de Freitas, Pádua Gracielle Teles, Delai Ruana Renostro, Freitas Aaronson Ramathan, Farinhas João Henrique, de Paula Luiza Gabriella Ferreira, Giuffrida Rogério, Pimpão Claudia Turra, Álvares Santarém Vamilton, Dos Santos Andrea Pires, Figueiredo Fabiano Borges, Krawczak Felipe da Silva, Biondo Alexander Welker
Laboratory of Cell Biology, Instituto Carlos Chagas, Fundação Oswaldo Cruz, Curitiba, Brazil.
School of Veterinary Medicine and Animal Science, Federal University of Goiás, Goiânia, Brazil.
Transbound Emerg Dis. 2022 Nov;69(6):3597-3605. doi: 10.1111/tbed.14723. Epub 2022 Oct 19.
Non-fatal cases of rickettsial infection with different clinical features than the classic BSF (Brazilian Spotted Fever) have been reported in seashore areas of Paraná state, southern Brazil. In addition, Amblyomma ovale tick infected by Rickettsia parkeri strain Atlantic rainforest has been also described in this area. Accordingly, the aim of this study was to investigate the occurrence of anti-Rickettsia spp. antibodies in human and dog populations, and Rickettsia spp. infection in ticks from oceanic islands and seashore mainland cities of southern Brazil. Serum samples were collected from 328 persons and their 282 dogs from three islands and two seashore mainland cities. A total of 211 ticks were collected from dogs, identified as A. ovale and R. sanguineus. In overall, 40 of 328 (12.2%) human samples were seropositive for Rickettsia spp., including 21 of 190 (11.1%) on islands and 19 of 138 (13.7%) on seashore mainland, and 62 of 282 (22.0%) dog samples, including 31 of 153 (20.3%) on islands and 31 of 129 (24.0%) in seashore mainland areas. In overall, nine of 82 (11.0%) ticks were positive to real-time PCR assay targeting a fragment of the rickettsial gltA gene, including two of 64 (3.1%) Rickettsia sanguineus and seven of 18 (38.9%) A. ovale, of which four were infected with the R. parkeri strain Atlantic rainforest. Despite no association between risk factors and Rickettsia spp. seropositivity was found in human beings, access to natural areas (p = .011) and tick infestation (p = .004) was significantly associated to dog seropositivity. The serological and molecular findings herein have confirmed previous tick and clinical case reports and enlarged the geographical occurrence of A. ovale infected by R. parkeri strain Atlantic rainforest in oceanic islands and seashore mainland cities of Paraná State, indicating a new likely transmission area of this new rickettsial infection in human beings and dogs of southern Brazil.
在巴西南部巴拉那州的海滨地区，已报告了一些立克次体感染的非致命病例，其临床特征与典型的巴西斑点热不同。此外，在该地区还发现了感染帕克立克次体大西洋雨林株的卵形钝眼蜱。因此，本研究的目的是调查巴西南部海洋岛屿和海滨大陆城市的人类和犬类群体中抗立克次体属抗体的出现情况，以及蜱中是否存在立克次体属感染。从三个岛屿和两个海滨大陆城市的328人及其282只狗身上采集了血清样本。共从狗身上采集了211只蜱，鉴定为卵形钝眼蜱和血红扇头蜱。总体而言，328份人类样本中有40份（12.2%）立克次体属血清学阳性，其中岛屿上190份样本中有21份（11.1%），海滨大陆上138份样本中有19份（13.7%）；282份犬类样本中有62份（22.0%）血清学阳性，其中岛屿上153份样本中有31份（20.3%），海滨大陆地区129份样本中有31份（24.0%）。总体而言，82只蜱中有9只（11.0%）针对立克次体属gltA基因片段的实时PCR检测呈阳性，其中血红扇头蜱64只中有2只（3.1%），卵形钝眼蜱18只中有7只（38.9%），其中4只感染了帕克立克次体大西洋雨林株。尽管在人类中未发现危险因素与立克次体属血清学阳性之间存在关联，但进入自然区域（p = 0.011）和蜱虫叮咬（p = 0.004）与犬类血清学阳性显著相关。本文的血清学和分子学研究结果证实了先前的蜱虫和临床病例报告，并扩大了巴拉那州海洋岛屿和海滨大陆城市中感染帕克立克次体大西洋雨林株的卵形钝眼蜱的地理分布范围，表明巴西南部人类和犬类中这种新型立克次体感染可能存在新的传播区域。
